Target names for executables now take into account suffixes.

In previous versions of meson, a meson.build file like this:

exectuable('foo', 'main.c')
exectuable('foo', 'main.c', name_suffix: 'bar')

would result in a configure error because meson internally used the same id for both executables. This build file is now allowed since meson takes into account the bar suffix when generating the second executable. This allows for executables with the same basename but different suffixes to be built in the same subdirectory.